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- .Dd September 8, 2016
- .Dt EXIT 2
- .Os
- .Sh NAME
- .Nm _exit
- .Nd terminate the calling process
- .Sh LIBRARY
- .Lb libc
- .Sh SYNOPSIS
- .In unistd.h
- .Ft void
- .Fn _exit "int status"
- .Sh DESCRIPTION
- The
- .Fn _exit
- system call
- terminates a process with the following consequences:
- .Bl -bullet
- .It
- All of the descriptors open in the calling process are closed.
- This may entail delays, for example, waiting for output to drain;
- a process in this state may not be killed, as it is already dying.
- .It
- If the parent process of the calling process has an outstanding
- .Xr wait 2
- call
- or catches the
- .Dv SIGCHLD
- signal,
- it is notified of the calling process's termination and
- the
- .Fa status
- is set as defined by
- .Xr wait 2 .
- .It
- The parent process-ID of all of the calling process's existing child
- processes are set to the process-ID of the calling process's reaper;
- the reaper (normally the initialization process)
- inherits each of these processes
- (see
- .Xr procctl 2 ,
- .Xr init 8
- and the
- .Sx DEFINITIONS
- section of
- .Xr intro 2 ) .
- .It
- If the termination of the process causes any process group
- to become orphaned (usually because the parents of all members
- of the group have now exited; see
- .Dq orphaned process group
- in
- .Xr intro 2 ) ,
- and if any member of the orphaned group is stopped,
- the
- .Dv SIGHUP
- signal and the
- .Dv SIGCONT
- signal are sent to all members of the newly-orphaned process group.
- .It
- If the process is a controlling process (see
- .Xr intro 2 ) ,
- the
- .Dv SIGHUP
- signal is sent to the foreground process group of the controlling terminal,
- and all current access to the controlling terminal is revoked.
- .El
- .Pp
- Most C programs call the library routine
- .Xr exit 3 ,
- which flushes buffers, closes streams, unlinks temporary files, etc.,
- before
- calling
- .Fn _exit .
- .Sh RETURN VALUES
- The
- .Fn _exit
- system call
- can never return.
- .Sh SEE ALSO
- .Xr fork 2 ,
- .Xr sigaction 2 ,
- .Xr wait 2 ,
- .Xr exit 3 ,
- .Xr init 8
- .Sh STANDARDS
- The
- .Fn _exit
- system call is expected to conform to
- .St -p1003.1-90 .
- .Sh HISTORY
- The
- .Fn _exit
- function appeared in
- .At v7 .
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